Study On Sequence Stratigraphy And Hydrocarbon Reservoir Forming Of The Fu-yang Oil Layers In Chao45 Block

Using seismic, logging, cores data, Fuyu reservoir in Chao 45 block is divided into two third-order sequences and eighteen laminas, and each lamina is corresponding with one single channel. By the analysis of heavy mineral, it thinks that Fuyu reservior is restricted by south Huaide sedimentary system and its provenance comes from south area. On the basis of division and comparison of sequences, sedimentary micro-facies is researched by comprehensive using logging data and core data, we think that Fuyu reservior in this area mainly developed delta plain subphase deposition, and delta front facies only exists on top of Quansiduan. Sedimentary micro-facies develops distributary channel, distributary interchannel, sheet sand, natural levee, crevasse splay, far sandbar and so on, in which the mainly types are distributary channel and distributary interchannel. According to lack of petrophysical and dymamic date, empirical formulas interval transit time and natural gamma are used to calculate porosity, and fitting formula that is established by porosity and permeability predicts the permeability in this area, and furthermore to study the reservior heterogeneity. The research indicates that Fuyu reservior in this area is low porosity and low permeability reservoir whose heterogeneity is very high and the most reservior is distributary channel sand bodies. Because this area is on the top of Palaeostructure development, Sanzhao depression Qingshankou group vertical reservoir and its lateral migration of hydrocarbon are still the main hydrocarbon source in this reservior. Through the research on geological and geochemical feature of hydrocarbon source rocks and hydrocarbon generation and expulsion intensity, we think that a part oil source of Fuyu reservior in this area is from Qingyiduan source rock. At last ,by the comprehensive analysis of the reservoir forming elements and their matching relationship, which includes reservation, cover, enclose, migration, maintain etc, reservoir type is determined as fault-lithology composite reservoir and the main reservoir forming factors are overpressure, fault and sand body. On the basis of research above, hydrocarbon migration and accumulation mode of this area is proposed.